21800063 has 4 divisors (see below), whose sum is σ = 22098768. Its totient is φ = 21501360.

The previous prime is 21800059. The next prime is 21800081. The reversal of 21800063 is 36000812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21800063 - 2² = 21800059 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21800003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 149243 + ... + 149388.

It is an arithmetic number, because the mean of its divisors is an integer number (5524692).

Almost surely, 2^21800063 is an apocalyptic number.

21800063 is a deficient number, since it is larger than the sum of its proper divisors (298705).

21800063 is an equidigital number, since it uses as much as digits as its factorization.

21800063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 298704.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 21800063 is about 4669.0537585254. The cubic root of 21800063 is about 279.3525132253.

Adding to 21800063 its reverse (36000812), we get a palindrome (57800875).

The spelling of 21800063 in words is "twenty-one million, eight hundred thousand, sixty-three".